Using Extensible 3D (X3D) Graphics for Web-based Accessibility and
Visualization

Many new opportunities are now available for use of 3D graphics for
visualization and spatialized auralization of buildings, human interactions,
interpretable data and arbitrary objects via the Web. The Extensible 3D (X3D)
Graphics specifications are a family of ISO standards that define the syntax,
rendering and behavior of Web-based interactive real-time 3D graphics. X3D
offers an XML encoding, classic Virtual Reality Modeling Language (VRML)
encoding, and extensible application programming interfaces (APIs) for both
Ecmascript and Java known as the Scene Authoring Interface (SAI). A matched
set of XML DTDs and XML Schema ensures strict syntactic compliance with the
abstract functionality of X3D. These combined capabilities allow 3D authors
to define interactive content that contains lightweight, consistently
viewable scenes. An open standard, multiple implementations, open source
exemplars and close partnerships make X3D fully ready for Web pages that are
tightly integrated and multimodal. Many aspects of the Web Accessibility
Inititiative (WAI) can benefit from this technology.

While X3D capabilities are quite expressive and technically impressive in
their own right, more work needs to be done to apply WAI principles and
practices to improve 3D navigability and accessibility. In general, 3D
navigation is problematic in that no two applications have an identical
navigation interface. Given inconsistent implementations across all 3D
applications, "lost in cyberspace" is a commonplace condition. Indeed,
everyone might be considered "access impaired" with respect to untutored 3D
interaction. Deliberate application of well-documented WAI principles might
have broad and immediate benefit to 3D websites. The availability of
internationalization (I18N) tooltips, "class" attributes and a well-defined
interface hierarchy provide further technical assets. Thus overall 3D
accessibility goals need to include building a foundation for repeatable
progress.

Future outcomes from using 3D in accessibility might be profound. One
visualization objective now achievable is defining 2D/3D documentation
standards for recommended access to public buildings by individuals with
physical-access impairments. Other areas of mutual interest involve the
Humanoid Animation (H-Anim) standard, which defines canonical body joints and
segments. One Web3D company has implemented American Sign Language (ASL)
alphabet and vocabulary as a behavioral gesture library reusable by various
humanoid avatars - such work might well be standardized for broader use.
Gestural libraries have further implications for I18N and human-machine
interaction, since different bodies, dress, localization (L10N) variations,
and output modes are already possible.

Much important work awaits. Web-based 3D graphics will have major impacts
on usability and accessibility. X3D now provides the necessary XML-compatible
technology needed to pursue these objectives in concert with other multimodal
research. Shared, WAI-inspired strategies on 3D-capable visualizations are
needed to guide and shape these efforts, so that effective and repeatable
common practices result.